Means for maintaining constant delivery from a fluid circuit



Nov. 24, 1959 R.- A. JOBUS ETAL 2,914,253

MEANS FOR MAINTAINING CONSTANT DELIVERY FROM A FLUID CIRCUIT Filed May25, 1956 I 2 Sheets-Sheet 1 ml mm FIG. I.

R'A. JOBUS H. G. WALTHER INVENTORS ATTORNEYS Nov. 24, 1959 R. A. JOBUSET AL MEANS FOR MAINTAINING CONSTANT DELIVERY FROM A FLUID CIRCUIT FiledMay 25, 1956 2 Sheets-Sheet 2 R. A. JOBUS H. 6. WALT/ ER INVENTORS M, M,MW

ATTORNEYS United States Pat fct) MEANS FOR MAINTAINING CONSTANT DELIVERYFROM A FLUID CIRCUIT Richard A. Johns, Chicago, Ill., and Herbert C.Walther,

Minneapolis, Minn., assignors to Continental Can Company, Inc., NewYork, N.Y., a corporation of New ork Application May 25, 1956, SerialNo. 587,397

1 Claim. (Cl. 239-75) The invention of which the following specificationis a description, relates to means for maintaining a constant rate ofvolume delivery from a fluid circuit.

In applying a sealing compound to container closures, the presentpractice involving high speed of operation demands that a constantvolume of lining compound be deposited on each closure.

It is usual to work with a lining compound which may have a range ofabout 20% to about 70% total solids, part of which is in a dispersedcolloidal state. 'Such com pounds are normally run at compoundtemperatures of between 60 F. and 120 P. which temperatures fiuctuatewith the variation of ambient temperature around the lining machine.Within this range of temperature there is a great variation in thevolume of flow delivered from the nozzle orifice of fixed size under aconstant pressure condition.

It is well understood that adjustment in the size of the nozzle tocompensate for such-changes in viscosity is impractical due to therapidity of operation which is on the order of 600 closures lined perminute.

The volume of compound which is to be deposited on each closure must beconstant. The delivery of such a normal, constant volume withoutadjustment at the delivery nozzle can be obtained since the pressure ofthe fluid stream at the nozzle can be made to vary with the viscosity,that is, inversely to changes in temperature.

ice

' pressure control;

Fig. 2 is an enlarged side elevation of the pressure control means takenon the line 2-2 of Fig. 1;

Fig. 3 is a similar front elevation of the same;

Fig. 4 is a fragmentary enlarged side elevation of a modified form ofthermostat;

Fig. 5 is a similar front elevation of the same, and

Fig. 6 is an enlarged vertical section of a modified form of regulatingvalve in the device shown in Figs. 1, 2 and 3.

To effectively maintain a constantvolume of delivery from the spraynozzle, means have been provided to recirculate the supply of fluidlining compound with attendant control of the flow by means of a devicewhich counteracts the change in viscosity caused by variation intemperature of the lining compound.

As shown in Figs. 1, 2 and 3, the novel arrangement includes a tank 7 inwhich a supply of lining compound may be placed and replenished fromtime to time as consumed.

When the replenish supply is at a different viscositytemperature thanthat already in the system by placing it in the tank outside the cup itdoes not affect the thermostat or discharge until it has circulatedthrough the systern and returned to the cup due to the 100 to 1 ratio ofIt has been found that direct control of such pressure and consequentlyconstant delivered volume is to be had by maintaining a circulation ofthe lining compound to the nozzle, returning the excess to the supplytank and varying the back pressure in the line to compensate fortemperature changes and resultant variations in viscosity.

Thus, a practically constant volume is obtained at the discharge fromthe nozzle regardless of changes in temperature of the compound withinthe range indicated.

It is easily understood that when the temperature of the compound in aclosed circuit from the supply tank to the nozzle and return is reduced,the compound tends to increase in viscosity. As this would normallydecrease the volurne of discharge from the nozzle, the decrease indischarge can be corrected by increasing the back pressure. By suchincrease of the back pressure the volume of discharge from the nozzlecan be maintained constant.

The present invention, therefore, has the purpose of providing means tomaintain the discharge from the delivery nozzle constant regardless ofchanges of viscosity due to variations in temperature.

A further object of the invention is to provide means by which anormally viscous lining compound can be quickly controlled in dischargefrom a nozzle of fixed size so that the volume of discharge remainsconstant.

The above and other objects of the invention will be readily understoodfrom the following description of the preferred form of our invention asillustrated by Way of example on the accompanying drawing in which:

Fig. l is a schematic diagram partly in section showcirculation todischarge.

'Centrally supported on a spider 8 in the tank 7 is a cup 9. The cup 9is at all times maintained full of the compound being applied. v

Tank 7 has a drain pipe 10 in the bottom by which lining compound iswithdrawn foruse.

The drain pipe 10 leads to a gear pump 11. This is representative ofnumerous types of pumps which may be used, the important feature beingthe fact that the pump will have constant displacement of the liquidbeing transferred. 7

. A pipe 12 extends from the delivery side of the pump 11 and mergeswith a return pipe 13 which has its end 14 within the upper part of thetank 7.

The return pipe has a thermometer 15 and a pressure gage 16 by which thecondition of the returning com-. pound may be observed.

The pipe 12 leads directly to the discharge or spray nozzle 17. Theusual ratio is that the volume of compound delivered to the spray nozzleand discharged therefrom shall be probably one part in volume of theamount circulating in the system.

A timing device 19 controls'the intermittent discharge of the compoundfrom the nozzle 17. This is intercalated with the operation'of'the'machine which presents the' can ends for deposit of the liningcompound thereon.

The tank 7 supports a bracket 20 from which hangs a thermostatic clamp21. This clamp extends to within a short distance of the bottom of thecup 9. The end 14 of the pipe has a flexible or elastic section 22. Thissection traverses the thermostatic clamp and the effective aperture ofthe section is controlled by the latter.

The clamp includes an upper fixed cross bar 23 attached to the bracket20. Two parallel rods 24, 24 extend vertically downward from the crossbar 23 to within a short distance of the bottom of the cup. The lowerends of the rods 24 are connected by a lower cross bar 25.

A slide bar 26 is slidably carried on the rods 24,24. This slide barcarries a lower pillow block 27 on its upper surface.

The slide bar 26 is supported by a center rod 28. This rod 28 isadjustably mounted on the lower cross bar 25. 1

An uppper pillow block 29 extends between the rods 24, 24, and partiallyencircles them. An adjusting screw 30 passes from the upper pillow block29 through the Patented Nov. 2 4, 1959 3 fixed cross bar 23 and'thebracket 20. A hand wheel or other adjusting means is provided at theother end of the adjusting screw.

The center rod 28 is made of a metal which has a greater coeflicient ofthermal expansion than the parallel rods 24, 24. Thus the rod 23 may bemade of steel and the rods 24, 24 of aluminum. The flexible section 22of the return pipe is constricted between the pillow blocks 27 and 29 inthe manner shown in Figs. 2 and 3. The center rod 28 responds to changesin temperature of the return compound by changing the amount ofconstriction of the flexible pipe section.

By adjusting the upper pillow block 29 this constriction can be made tocompensate closely for the change in back pressure caused by theabnormal change in viscosity of the returning compound.

The discharge end of the pipe section 22 connects with the vertical pipesection 32 which delivers into the cup 9 near its bottom.

Assuming the tank 7 to contain the desired quantity of viscous liningcompound, the compound will be withdrawn at the bottom and givenpositive circulation by the pump 11. I

The circulation is maintained at perhaps one hundred times the dischargefrom the nozzle 17. Granting that the discharge from the nozzle is thenormal volume, the return through the thermostatic clamp will be ofminimum restriction.

' However, if the lining compound increases in viscosity, there is thepossibility that under such circumstances discharge from the nozzle willdecrease with subnormal back pressure developing in the return pipe. Tocounteract such a condition, the thermostatic clamp will constrict toallow less return flow and thus increase the pressure at the nozzle.When the viscosity is lowered, the thermostatic clamp will enlarge thevalve section until the normal pressure is applied to the nozzle and thedischarge again is constant.

In the form shown in Fig. 4, the lower cross bar 35 is bi-metallic andresponsive to changes in temperature and the upper cross bar 34 isbi-metallic but arranged in reverse direction of movement. Thus theinner pair of leaves may be iron and the outer pair brass. The side rods36 are shorter than the rods 24 and need only extend far enough toencompass the flexible pipe section 22. The change of temperature of thecompound passing through the flexible pipe22 is sufficient to actuatethe bi-metallic elements to constrict the flow as the temperature islowered and increase the flow at the constriction as the temperature isincreased.

Adjusting nuts 37, 37 are threaded on the rods 36 so that the bars 34,35 may be brought together enough to establish the desired constrictionof the pipe section 22 within the range of temperature variationexperienced.

In the devices shown in Figs. 4 and 5 the bi-metallic strips 34 and 35respond to changes in temperature of the returning compound. The passageof relatively thin, high temperature compound through the pipe section22 will cause the bi-metallic members 34, 35 to bow outward and thusenlarge the pipe opening. However, slower passage of the viscous andrelatively cooler compound will cause the members 34, 35 to contract andthus partially close the flexible valve.

Fig. 6 shows how a different form of constricting valve may be arrangedin the modification shown in Figs. 1, 2 and 3. The upper cross bar 29 isreplaced by a pipe fitting 38. This pipe fitting is fitted between twoportions 39 and 40 of the flexible pipe section 22.

A pair of side rods 41, 41 correspond to the rods 24, 24. The center rod28 is the same as previously described. It terminates at its upper end,and within the pipe fitting 38, in a valve 42. The opposite portion ofthe fitting 38 is hollowed out to form a valve seat 43 complementary tothe shape of the valve 42.

The operation of the form shown in Fig. 6 is the same as that in Fig. 3.The advantage in this instance, however, is in the permanence of thevalve and its freedom from deterioration.

The arrangement above described provides for a ready and effective meansfor maintaining constant flow in the pipe circuit feeding a sprayingnozzle or the like.

While the preferred form of the invention has been shown and described,it is to be understood that the invention is not limited to said formsor other than by the scope of the appended claim.

What we claim is:

In combination with a discharge nozzle for a lining compound and thelike, a tank for the compound, piping from the tank to the nozzle, aconstant volume pump in said piping, a return pipe from the nozzle intothe tank, a compressible section in said return pipe, a bracket in saidtank, a pair of parallel rods depending from the bracket, a central rodbetween said parallel rods, a cross bar journaled on said parallel rodsand supported adjustably by said central rod beneath the compressiblesection and an upper cross bar journaled on said parallel rods andadjustably suspended from the bracket above the compressible section,said parallel rods and central rod having dissimilar coefiicients ofthermal expansion.

References Cited in the file of this patent UNITED STATES PATENTS2,199,454 Andler May 7, 1940 FOREIGN PATENTS 513,550 Germany Nov. 29,1930 1,014,791 France June 18, 1952

